1. Field of the invention
The present invention relates to a spanner generally used as a typical tool for tightening or releasing a hexagonal headed bolt or nut, more particularly to a spanner capable of tightening or releasing a bolt continually in one direction by the effect of a toggle bar pivotally mounted on a jaw of two jaws of the spanner head in a state that the toggle bar is urged to pivot toward one direction.
According to the present invention, if a user turns the spanner in clockwise direction, the rotating force of the spanner is applied to the bolt head so that the bolt head is tightened or released by the spanner, whereas, if a user turns the spanner in counter clockwise direction, the toggle bar is swung upwardly to be idle from the bolt head so that the rotating force of the spanner is not applied to the bolt head, thereby the spanner is capable of tightening or releasing a bolt continually in one direction while maintaining the hexagonal head of the bolt within the spanner head.
2. Description of the Related Art
A spanner generally used for tightening or releasing a hexagonal headed bolt or nut includes a lever provided with two jaws on an end, and each jaw has opposite surface parallel to each other for receiving a bolt or nut therebetween to rotate it. As typical types of a generally used spanner, there are a fixed type spanner having two jaws spaced apart from each other with a fixed distance, and an adjustable type spanner having a fixed jaw and a movable jaw capable of moving toward or away from the fixed jaw.
Another typical type of a generally used tool for tightening or releasing a bolt or a nut is a box wrench. A box wrench having a ratchet mechanism is also broadly used, which is constructed that the rotating force of the ratchet box wrench is applied to the bolt head so as to be tightened or released when turning the ratchet box wrench only in a predetermined direction of clockwise or counter clockwise direction thereby being capable of tightening or releasing a bolt continually in one direction.
In operations for tightening or releasing a bolt, a user determines which one is better between a spanner or a box wrench in consideration of the working conditions, such as working space for operation of the tool or location of bolt or nut fastened, etc., and uses the selected tool. In case of using a box wrench, especially a ratchet box wrench, it is possible to tighten or release a bolt continually in one direction while maintaining a state that the bolt or nut is inserted within the head of the box wrench, and which would increase the working efficiency.
However, certain working conditions require only a spanner. Being different from a ratchet box wrench, a conventional spanner is not capable of tightening or releasing a bolt continually in one direction, therefore, a user has to insert a bolt head within the head of the spanner to be engaged with the bolt head repeatedly each time after turning the spanner at a predetermined angle, for example 60 degrees for tightening or releasing a bolt or nut, and which would decrease the working efficiency.
In relation to this problem, there have been some attempts to provide a spanner having a ratchet mechanism capable of tightening or releasing a bolt continually in one direction, such as Korean Patent Laying-Open Publication No. 2000-0000449, Korean Patent Laying-Open Publication No. 1999-0028347, Korean Utility Model Reg. Publication No. 20-0243241, and Korean Utility Model Reg. Publication No. 20-0261440. However, these spanners have a problem that the construction of the spanner head become complex since a ratchet mechanism itself has a complex construction, accordingly the volume of the spanner head becomes too large, which makes the spanner loose its own merit of being convenient for operation in a slim working space.
Therefore, it is requested to develop a new spanner capable of tightening or releasing a bolt continually in one direction while maintaining its own merit of being convenient for operation in a slim working space.
In the mean time, the conventional spanner has another problem that respective distal ends of two jaws are opened parallel to each other so that the spanner is readily disengaged from the bolt head during operation, and this is quite inconvenient especially when a user holds the spanner vertically during operation for tightening or releasing a bolt or nut since he has to urge the spanner upwardly in order for turning the spanner. Therefore, it is requested to develop an improved spanner which further includes a protrusion disposed on a distal end of at least one jaw for gripping a bolt head, preferably an angular portion of a bolt head thereby the spanner is capable of maintaining the state that the bolt head is inserted therein even though a user takes his hand off the spanner when he holds the spanner vertically during operation for tightening or releasing a bolt or nut. The present invention has been made to fulfill above two requests.